The existence of lymphatic vessels in the dental pulp has been surrounded by controversy. In the first study to use perfusion fixed specimens we have recently shown in cats that pulp lymphatic vessels are always present. However their distribution in different teeth and the sites of origin of their end bulbs remain in doubt. In order to gain further insight into this problem it will be necessary to develop a new method for readily identifying the lymphatic vasculature of the dental pulp. We aim to do this by filling the pulp lymphatic vasculature with a colored silicone rubber based material (Microfil). The plan includes three distinct phases as follows: (1) Identification outside the tooth of lymphatic vessels which drain lymph originating from pulp (extradental vessels). (2) Experiments to demonstrate that retrograde perfusion of the extradental vessels is effective in reaching the pulp. (3) Retrograde perfusion to fill the lymphatic vasculature inside the pulp. The central objective of this project is to develop a technique. In the longer term it will then be possible to describe the lymphatic distribution in relation to other structures in the pulp with light microscopy. This will lead to a better understanding of normal pulp physiology. In addition it may provide insight into the remarkably variable symptoms and progress of pulpitis. Looking further ahead the retrograde perfusion method could be applied to scanning and transmission electron microscopical methods in normal as well as experimentally induced disease conditions.